Wanted: Rear Traction!

SLOroadster · Post by **SLOroadster** » Mon Mar 21, 2005 12:18 am

What does a Bellville type LSD look like? I didn't know there were different types for the roadster. I'd like to see a picture and compair it to what I have (currently sitting in a box, waiting for a new axle)

Will

nomadtrash · Post by **nomadtrash** » Sun Mar 27, 2005 7:31 pm

Belleville makes reference to the types of plates inside the differential. The Belleville differential has a disc and plate on each end that are concave instead of flat. They are springy and provide a more forgiving lock-up than the standard clutch pack. The outside of the LSD is the same and you won't be able to tell the difference without taking the side plate off. Gordon has a good write up on the differentials.

I do have a torque arm. I had replaced the soft rubber bushings with delrin and made the shaft so that it would rotate but I think it was binding up. I plan on building a new torque arm with shperical rod ends.

There is a balancing act between having a too tight differential. If it is too loose then there is no traction. If it is too tight then there is a lot of understeer entering the corner and oversteer exiting. If it is just right then you get the neutral handling and traction. I will have to set mine by trial and error.

SLOroadster · Post by **SLOroadster** » Sun Mar 27, 2005 8:40 pm

Andy,
Thanks for the info. I think my LSD is setup with a little too much preload, the car will push a bit entering a corner, but the backend will step out in a real big way if Im not very carefull. I don't really like the way the car handles with the open 3.9 that it currently has on it, however I should try my rear swaybar with it to see if it will help keep the rearend planted, as it is now it lifts the inside wheel through a tight sweeping corner. With the LSD and the swaybar, it was mega oversteer central, (but was lots of fun to spin donuts in

)

Will

nomadtrash · Post by **nomadtrash** » Sun Mar 27, 2005 9:10 pm

The swaybar will make it lift the inside tire more. There is too much body roll even with the comp springs and swaybar in front. The trick that some use is to get the early rear springs that have less rate than the comp springs. This allows the inside tire to flaa down farther and not lift as much during cornering. It is a patch for a problem and not a cure. The front springs need to be much stiffer than the comp springs and the swaybar needs to be larger than the 22mm or 23mm units that were available. Some race cars use a torsion bar as a swaybar. I think Randy has some good spring rate advise on the production racing site. My car still leans too much even though it only weighs 1650 pounds. I will go with stiffer springs eventually. I have to come up with some money first.

Post by **dbrick** » Sun Mar 27, 2005 10:26 pm

Just curious, how did you get 400 pounds out of a roadster???

nomadtrash · Post by **nomadtrash** » Sun Mar 27, 2005 10:35 pm

A bunch of the car is fiberglass now. Everything that could be unbloted has been removed. Things that couldn't be unbolted were cut off. I plan to get it down to 1450 eventually.

SLOroadster · Post by **SLOroadster** » Mon Mar 28, 2005 1:09 am

Andy,
Good call on the rear swaybar, you caught me thinking again (I really need to quit doing that

) Do you have any ideas on endlinks for the front swaybar, my car seems to eat the one on the driver side on a regular basis, currently I have run out of them. I'd like to figure out how to make the front end a coil-over setup.
At 1600 lbs, I don't care what engine is in a roadster, its going to be a rocket. Heck an R16 would be fun at that weight.

Will

nomadtrash · Post by **nomadtrash** » Mon Mar 28, 2005 7:31 am

I made some from delrin They are the same shape as the OEM but are really hard. The stock retainer is still being used. I don't have a problem with losing end links even when using the stock ones. Other swaybar setups use a different mounting location with struts that go to the upper a-arm.

SLOroadster · Post by **SLOroadster** » Mon Mar 28, 2005 10:21 am

I keep breaking the retainers, but just on one side. Eh just another thing to have to fix before I take it out to the autoX course.

Will

nomadtrash · Post by **nomadtrash** » Mon Mar 28, 2005 2:27 pm

You may have a bent mounting tower. It is common to tow, tie down, jack, etc... on the swaybar towers but they are not strong enough for that. It is easy to bend the towers forwards. If your towers are out of whack it would cause the swaybar to not fit in the lower a-arm correctly and would pull on the retainer under load. It might also cause funky handling since you would be wedging the car. It might work well for dirt track if you are so inclined.